Method of cutting bodies soluble in liquid



Jan. 17, 1939. E GERLACH 2,144,370

METHOD OF CUTTING BODiES SOLUBLE IN LIQUID Filed July 3, 1937 INVENTOR ERWIN G'ERLACH ATTORNEY Patented Jan. 17, 1939 Y METHOD OF CUTTING BODIES SOLUBLE 1N meow Gerlach, mriin, Germany, assignor to Erwin Teleiunken Gesellschaft fiir Drahtlose Telegraphic in. b. E, Berlin, Germany, a corporation 01' Ge u s (r.

-Application my a, 1937, Serial No. 151,951 In Germany .Fnly 10, 1936 s Glaims. (ci. 125-21) This invention relates to a method of cutting thin layers from bodies which are soluble in liquid, in partlcular crystals such as Rochelle salt or other crystals. q

Bodies soluble in liquid are usually cut by means oi a thread moistened with the solvent of the body to be cut. I Whencutting bodies in accordance with this method it was found that the cut surface is often unclean. It is especially at 10 the edges of the body to be cut and past which the thread moves that the liquid carried with the thread is rubbed ofl. But this liquid left behind at-the body eats into the surface of the crystal and it is especially the edges that are per- 15 ticularly exposed to this action. In piezo-electric crystals such as produced, for instance, of R- chelle salt, it is an absolute requirement that the edges of the crystal are clean and exact.

According to the, invention a clean, unobjectionable cut surface and a possible rapid cutting through the body to be cut through can be assured if the following conditions have the proper relationship.

The material of the thread depends on the 25 body to be cut through. In case of Rochelle salt, a thread of artificial silk was found to be an especially favorable material, yet also threads of rubber are well suited for the cutting. Of further importance is the speed of the thread. The 30 latter depends on the material of the thread and on the thickness of the body to be'cut. Then the amount of solvent applied to the thread is also of significance. At theplace of cutting, the thread should be not too moist and not toowet. Also, at this place, the amount of liquid to be applied depends on the type of the body to be cut and on its thickness. Finally, the feed is to be, set according to the type and thicmess of the body-to be cut.

40 tests for the respective kind of material to be cut.

ForRochelle salt and a cutting length of about 12 mm. and with a thread of artificial silk havin have been obtained at acutting speed (feed) ranging from 1 to 4 mm./min., a supply of liquid The optimum cutting must, be ascertained by a thickness of about 0,5 mm, favorable resultsmotor not shown in the figure. mo e 8 d p d between the rollers i and G the supply nozzle 6 for the liquid solvent of the" body to be cut, for

instance, a crystal ofRoohelle salt. The supply of the solvent can be controlled, but this-control arrangement is not shown herein. Between the rollers 3 and 4 the crystal i is clamped .into a support moved upon the thread 5 in the direction of the arrow.

The operation during cutting is as follows:

The solvent flows out of the nozzle 6 upon the thread 5, the latter moving in the direction indicated by the arrow. When the thread. moves over the driver roller i a part of the liquid is being thrown off, and this partial throwing ofi of the liquid from the thread occurs also when the latter passes over the other rollers. After leaving the roller 3, the thread passes over the crystal slightly loosening up the same at the place of cutting. Care must be taken that the thread is maintained in a partlymoist and partly dry state, that is, it must not carry too large an amount of liquid solvent, otherwise, a non-saturated solution will be deposited at the place at which the thread leaves the crystal. As a result thereof, the crystal is subjected to eating by said solution especially at the edges of the cut surface of the crystal.

When the thread leaves the crystal, the liquid still present on the thread is practically satu: rated with crystal molecules. Then the thread passes again over the roller i finally to be moved again past the nozzle 6 through which it is being moistened again whereby the solution thereon'will be diluted.

The quantity of solvent dripped onto the thread will, as previously pointed out, be partly thrown off when the thread 5 moves over the drive roller i. Theamount of liquid remaining to the thread at the place'of the nozzle in order that a possibly large number of dissolved molecules will be thrown off by the thread. In this way, the liquid on the thread can dissolve'at'the place of cutting a sufficient number of molecules of the body to be cut.

' In place of the endless thread passing in the same direction, a thread which carries'out a.

reciprocating movement may be used. In this case; two nozzles are preferably to be employed, the crystal being disposed between the two nozzles. Also, in. this case it is necessary that saturated solution be removed from the thread.

What is claimed is:

1. Method of cutting Rochelle salt crystals by means of a thread moistened with a solvent 0! the body to be cut, characterized in that by using an. endless thread of artificial silk with a thickness of about 0,5 mm. for cutting the crystal, the cutting speed (feed) is 1 to 4 mm/min, the liquid supply 2 to 16 mm /sec. and. the speed of the thread 1 to 3 m/sec. at a cutting length of about 12 mm.

2. Apparatus for cutting Rochelle salt crystals comprising a first roller, a second roller, a third roller and a fourth roller, an endless thread placed around said rollers, means for driving at least one of said rollers,- means for keeping said endless thread moistened by a liquid solvent of said crystal, said last mentioned means located between said first and fourth rollers, and a support for the crystal to be cut located between said third and fourth rollers.

4 3. Apparatus for cutting Rochelle salt crystals comprising a first roller, a second roller, a third roller and a fourth roller, an artificial endless threadplaced around said rollers, means for assasvo driving at least one of said rollers, means including a nozzle iorkeeping said endless thread moistened by a liquid solvent of said crystal, said last mentioned means located between said first and fourth rollers, and a support for the crystal to be cut located between said third and fourth rollers.

4, Apparatus for cutting Rochelle salt crystals comprising a first roller, 9. second roller, a third roller and a fourth roller, an endless thread placed around said rollers, means for driving at least one 0! said rollers, means for keeping said endless thread moistened by a liquid solvent of said crystal, said last mentioned means located between said first and fourth rollers, and a clamp for supporting said crystal to be cut and located between said third and fourth rollers, said clamp having means for moving the crystal toward said thread. Y

5. Apparatus for cutting piezo-electric crystals comprising a plurality of rollers, an endless thread placed around said rollers, means for driving at least one of saidrollers, means for keeping said endless thread moistened by a. solvent of said crystal, and means for supporting said crystal in a position to be cut by said endless thread.

Erzwm' GERLACH. 

